/* =========================================================
   龙腾飞 APP 开发单页 —— 
   配色：龙腾飞品牌橙 (#ff5b00)
   独立 CSS 文件，含完整响应式
   ========================================================= */

:root{
  --primary:#ff5b00;
  --primary-d:#e64a00;
  --primary-l:rgba(255,91,0,0.08);
  --ink:#1a1e2e;
  --gray:#6B6560;
  --gray-l:#8D8880;
  --bg:#FAF8F5;
  --dark1:#12142a;
  --dark2:#1a1e3a;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  font-family:'Noto Sans SC',-apple-system,BlinkMacSystemFont,"Microsoft YaHei",sans-serif;
  background:var(--bg);color:var(--ink);line-height:1.7;
}
a{color:var(--primary);text-decoration:none}
a:hover{text-decoration:none}

/* ===== NAV ===== */
.nav{
  position:fixed;top:0;left:0;right:0;z-index:1000;
  background:rgba(250,248,245,0.92);backdrop-filter:blur(12px);
  border-bottom:1px solid transparent;
  transition:border-color .3s,box-shadow .3s;
}
.nav.scrolled{border-bottom-color:rgba(0,0,0,0.06);box-shadow:0 2px 20px rgba(0,0,0,0.04);}
.nav-inner{
  max-width:1200px;margin:0 auto;padding:0 32px;height:64px;
  display:flex;align-items:center;justify-content:space-between;
}
.nav-brand{display:inline-flex;align-items:center;gap:12px;text-decoration:none;}
.nav-logo{height:38px;width:auto;}
.nav-brand-text{font-size:20px;font-weight:900;color:var(--ink);letter-spacing:1px;display:flex;align-items:baseline;gap:8px;}
.nav-brand-desc{color:var(--primary);font-size:13px;font-weight:700;letter-spacing:0;white-space:nowrap;}
.nav-links{display:flex;gap:30px;list-style:none;}
.nav-links a{font-size:15px;font-weight:500;color:var(--gray);text-decoration:none;transition:color .2s;}
.nav-links a:hover{color:var(--primary);}
.nav-cta{
  background:var(--primary);color:#fff;font-size:14px;font-weight:600;
  padding:10px 22px;border-radius:10px;text-decoration:none;transition:background .2s;white-space:nowrap;
}
.nav-cta:hover{background:var(--primary-d);color:#fff;}
.nav-toggle{display:none;background:none;border:none;font-size:24px;cursor:pointer;color:var(--ink);}

/* ===== HERO ===== */
.hero{
  padding:140px 32px 80px;max-width:1200px;margin:0 auto;
  display:grid;grid-template-columns:1fr 1fr;gap:60px;align-items:center;
}
.hero-text h1{font-size:46px;font-weight:900;line-height:1.3;margin-bottom:20px;}
.hero-text h1 em{
  font-style:normal;
  background:linear-gradient(135deg,var(--primary),#ff8a3d);
  -webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text;
}
.hero-text .subtitle{font-size:19px;color:var(--gray);font-weight:400;margin-bottom:34px;line-height:1.8;}
.hero-btns{display:flex;gap:16px;flex-wrap:wrap;}
.btn-primary{
  background:var(--primary);color:#fff;font-size:16px;font-weight:600;
  padding:15px 34px;border-radius:12px;display:inline-flex;align-items:center;gap:8px;
  text-decoration:none;transition:all .2s;box-shadow:0 4px 16px rgba(255,91,0,0.25);
}
.btn-primary:hover{background:var(--primary-d);transform:translateY(-1px);color:#fff;}
.btn-secondary{
  background:#fff;color:var(--primary);font-size:16px;font-weight:600;
  padding:15px 34px;border-radius:12px;border:2px solid rgba(255,91,0,0.2);
  display:inline-flex;align-items:center;gap:8px;text-decoration:none;transition:all .2s;
}
.btn-secondary:hover{border-color:var(--primary);color:var(--primary);}
.hero-visual{display:flex;justify-content:center;align-items:center;position:relative;}
.hero-visual img{width:100%;max-width:420px;height:auto;filter:drop-shadow(0 20px 50px rgba(0,0,0,0.12));}
.hero-visual::before{
  content:'';position:absolute;width:360px;height:360px;border-radius:50%;
  background:radial-gradient(circle,rgba(255,91,0,0.10) 0%,transparent 70%);pointer-events:none;
}

/* ===== STATS BAR ===== */
.stats-bar{background:linear-gradient(135deg,var(--dark1),var(--dark2));padding:48px 32px;}
.stats-inner{max-width:1200px;margin:0 auto;display:grid;grid-template-columns:repeat(4,1fr);gap:32px;text-align:center;}
.stat-item .stat-num{font-size:46px;font-weight:900;color:var(--primary);line-height:1.2;}
.stat-item .stat-unit{font-size:20px;color:rgba(255,255,255,0.6);}
.stat-item .stat-label{font-size:15px;color:rgba(255,255,255,0.5);margin-top:8px;}

/* ===== SECTIONS ===== */
.section{padding:80px 32px;}
.section-alt{background:#fff;}
.section-dark{background:linear-gradient(135deg,var(--dark1),var(--dark2));color:#fff;}

.section-inner{max-width:1200px;margin:0 auto;}
.section-tag{font-size:13px;font-weight:700;color:var(--primary);letter-spacing:4px;text-transform:uppercase;margin-bottom:12px;}
.section-dark .section-tag{color:rgba(255,255,255,0.4);}
.section-title{font-size:36px;font-weight:900;margin-bottom:20px;line-height:1.3;}
.section-dark .section-title{color:#fff;}
.section-desc{font-size:17px;color:var(--gray-l);margin-bottom:48px;max-width:680px;line-height:1.8;}
.section-dark .section-desc{color:rgba(255,255,255,0.5);}

/* ===== SERVICE CARDS ===== */
.service-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:28px;}
.service-card{
  background:#fff;border:1px solid rgba(0,0,0,0.04);border-radius:16px;padding:40px 28px;
  box-shadow:0 2px 12px rgba(0,0,0,0.03);transition:transform .2s,box-shadow .2s;position:relative;overflow:hidden;
}
.service-card:hover{transform:translateY(-4px);box-shadow:0 8px 30px rgba(255,91,0,0.12);}
.service-card::before{content:'';position:absolute;top:0;left:0;right:0;height:4px;background:linear-gradient(90deg,var(--primary),#ff8a3d);}
.service-num{font-size:56px;font-weight:900;color:rgba(255,91,0,0.07);position:absolute;top:12px;right:20px;line-height:1;}
.service-icon{font-size:42px;margin-bottom:20px;display:block;}
.service-card h3{font-size:22px;font-weight:700;margin-bottom:12px;}
.service-card p{font-size:15px;color:var(--gray-l);line-height:1.8;}

/* ===== PROCESS ===== */
.process-flow{display:flex;align-items:flex-start;gap:20px;margin-top:48px;}
.process-step{flex:1;text-align:center;position:relative;}
.process-step::after{content:'→';position:absolute;right:-20px;top:28px;font-size:24px;color:rgba(255,255,255,0.2);}
.process-step:last-child::after{display:none;}
.process-dot{
  width:64px;height:64px;border-radius:50%;background:rgba(255,91,0,0.15);
  display:flex;align-items:center;justify-content:center;font-size:28px;margin:0 auto 16px;
}
.process-step h4{font-size:17px;font-weight:700;color:#fff;margin-bottom:6px;}
.process-step p{font-size:14px;color:rgba(255,255,255,0.45);line-height:1.6;}

/* ===== INDUSTRIES GRID ===== */
.industry-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:18px;}
.industry-card{
  background:#fff;border:1px solid rgba(0,0,0,0.04);border-radius:14px;padding:24px 20px;
  box-shadow:0 2px 12px rgba(0,0,0,0.03);transition:transform .2s,box-shadow .2s,border-color .2s;
}
.industry-card:hover{transform:translateY(-4px);box-shadow:0 8px 30px rgba(255,91,0,0.12);border-color:rgba(255,91,0,0.25);}
.industry-name{
  display:inline-block;font-size:17px;font-weight:700;color:var(--primary);
  padding:4px 0;margin-bottom:12px;border-bottom:2px solid var(--primary);
}
.industry-card p{font-size:14px;color:var(--gray-l);line-height:1.7;}

/* ===== ADVANTAGES ===== */
.adv-grid{display:grid;grid-template-columns:repeat(5,1fr);gap:18px;}
.adv-item{
  background:linear-gradient(135deg,#fff,#fff7f2);border:1px solid rgba(255,91,0,0.08);
  border-radius:16px;padding:32px 18px;text-align:center;transition:transform .2s,box-shadow .2s;
}
.adv-item:hover{transform:translateY(-4px);box-shadow:0 8px 26px rgba(255,91,0,0.14);}
.adv-ico{font-size:40px;margin-bottom:14px;}
.adv-item h3{font-size:16px;font-weight:700;color:var(--ink);line-height:1.6;}

/* ===== CASE GALLERY ===== */
.case-gallery{display:grid;grid-template-columns:repeat(5,1fr);gap:16px;}
.case-card{
  background:#fff;border:1px solid rgba(0,0,0,0.04);border-radius:16px;overflow:hidden;
  box-shadow:0 2px 12px rgba(0,0,0,0.03);transition:transform .2s,box-shadow .2s;
}
.case-card:hover{transform:translateY(-6px);box-shadow:0 10px 32px rgba(255,91,0,0.16);}
.case-card img{width:100%;height:100%;object-fit:cover;display:block;}

/* ===== PRODUCT SHOWCASE ===== */
.product-showcase{display:grid;grid-template-columns:repeat(4,1fr);gap:20px;}
.product-card{
  background:#fff;border:1px solid rgba(0,0,0,0.04);border-radius:16px;padding:20px;
  box-shadow:0 2px 12px rgba(0,0,0,0.03);transition:transform .2s,box-shadow .2s;text-align:center;
}
.product-card:hover{transform:translateY(-4px);box-shadow:0 8px 30px rgba(255,91,0,0.12);}
.product-card img{width:100%;max-width:260px;margin:0 auto;}

/* ===== CTA ===== */
.cta-section{
  background:linear-gradient(135deg,var(--dark1),var(--dark2));border-radius:24px;
  padding:64px 48px;text-align:center;position:relative;overflow:hidden;max-width:1000px;margin:0 auto;
}
.cta-section::before{
  content:'';position:absolute;inset:0;
  background:
    radial-gradient(circle at 30% 50%,rgba(255,91,0,0.12) 0%,transparent 50%),
    radial-gradient(circle at 70% 50%,rgba(255,138,61,0.08) 0%,transparent 50%);
  pointer-events:none;
}
.cta-section h2{font-size:38px;font-weight:900;color:#fff;margin-bottom:16px;position:relative;line-height:1.4;}
.cta-section .cta-desc{font-size:17px;color:rgba(255,255,255,0.5);margin-bottom:34px;position:relative;line-height:1.8;}
.qr-wrap{display:inline-block;padding:12px;background:rgba(255,255,255,0.1);border-radius:16px;border:1px solid rgba(255,255,255,0.1);position:relative;}
.qr-wrap img{width:200px;height:200px;border-radius:10px;display:block;}
.cta-hint{font-size:15px;color:rgba(255,255,255,0.45);margin-top:16px;position:relative;}
.cta-hint b{color:var(--primary);}
.cta-btns{display:flex;gap:14px;justify-content:center;margin-top:28px;position:relative;flex-wrap:wrap;}

/* ===== FOOTER ===== */
.footer{padding:48px 32px;text-align:center;border-top:1px solid rgba(0,0,0,0.04);}
.footer-brand{font-size:20px;font-weight:900;color:var(--ink);letter-spacing:2px;margin-bottom:12px;}
.footer-nav{display:flex;justify-content:center;gap:24px;margin-bottom:20px;list-style:none;}
.footer-nav a{font-size:14px;color:var(--gray-l);text-decoration:none;}
.footer-nav a:hover{color:var(--primary);}
.footer-copy{font-size:13px;color:#B0AAA2;line-height:1.9;}
.footer-copy p{margin:2px 0;}

/* ===== RESPONSIVE ===== */
@media(max-width:900px){
  .nav-brand-desc{font-size:12px;}
  .nav-links{display:none;}
  .nav-toggle{display:block;}
  .nav-links.open{
    display:flex;flex-direction:column;position:absolute;top:64px;left:0;right:0;
    background:rgba(250,248,245,0.98);backdrop-filter:blur(12px);
    padding:20px 32px;gap:16px;border-bottom:1px solid rgba(0,0,0,0.06);
  }
  .hero{grid-template-columns:1fr;gap:40px;padding:120px 24px 60px;text-align:center;}
  .hero-btns{justify-content:center;}
  .hero-visual{order:-1;}
  .hero-visual img{max-width:280px;}
  .hero-text h1{font-size:32px;}
  .hero-text .subtitle{font-size:17px;}
  .stats-inner{grid-template-columns:repeat(2,1fr);gap:20px;}
  .stat-item .stat-num{font-size:36px;}
  .section{padding:60px 24px;}
  .section-title{font-size:28px;}
  .service-grid{grid-template-columns:1fr;}
  .process-flow{display:grid;grid-template-columns:1fr 1fr;gap:24px;}
  .process-step::after{display:none;}
  .industry-grid{grid-template-columns:repeat(2,1fr);}
  .adv-grid{grid-template-columns:repeat(2,1fr);}
  .case-gallery{grid-template-columns:repeat(2,1fr);}
  .product-showcase{grid-template-columns:repeat(2,1fr);}
  .cta-section{padding:48px 24px;border-radius:16px;}
  .cta-section h2{font-size:28px;}
}
@media(max-width:480px){
  .nav-inner{padding:0 16px;}
  .nav-brand-text{font-size:18px;}
  .stats-inner{grid-template-columns:1fr 1fr;}
  .stat-item .stat-num{font-size:32px;}
  .industry-grid{grid-template-columns:1fr;}
  .adv-grid{grid-template-columns:1fr;}
  .case-gallery{grid-template-columns:1fr;}
  .product-showcase{grid-template-columns:1fr;}
  .btn-primary,.btn-secondary{padding:13px 26px;font-size:15px;}
}